argocd-server ran --insecure (plain HTTP :8080) while its Helm-managed
Ingress set ssl-passthrough: true, which sends nginx's raw TLS handshake
straight to the pod - HTTP server can't complete a TLS handshake, nginx
logged 502 (peer closed connection in SSL handshake). Compounded by a
second, conflicting Ingress for the same host in
k8s/bootstrap/ingress/ingress.yaml - two Ingress objects on one host is
undefined nginx routing behavior. Disabled the Helm-managed Ingress
(enabled: false) so ingress.yaml's passthrough Ingress is the sole
source of truth, and set server.insecure: false so argocd-server
actually terminates TLS itself, matching passthrough's requirement.